1. Field of the Invention
The present invention relates to the formation of transistors via shadow mask vapor deposition events and, more particularly, to the formation of a transistor via shadow mask vapor deposition events in a manner that avoids damage to the semiconductor material of the transistor due to the undesirable discharge of static electricity that accumulates on a shadow mask during a shadow mask vapor deposition event.
2. Description of Related Art
Active matrix backplanes are widely used in flat panel displays, such as LCDs, for routing signals to pixels of the display in order to produce viewable pictures. Presently, such active matrix backplanes are formed by use of a photolithography manufacturing process, which has been driven in the market by the demand for higher and higher resolution displays which are not otherwise possible with other manufacturing processes. Photolithography is a pattern definition technique that uses electromagnetic radiation, such as ultraviolet (UV) radiation, to expose a layer of resist that is deposited on the surface of a substrate. Exemplary photolithography processing steps to produce an active matrix backplane include coat photoresist, pre-bake, soak, bake, align/expose, develop, rinse, bake, deposit layer, lift off photoresist, scrub/rinse and dry. As can be seen, the active matrix backplane fabrication process includes numerous deposition and etching steps in order to define appropriate patterns of the backplane. Because of the number of steps required to form an active matrix backplane by use of the photolithography manufacturing process, foundries of adequate capacity for volume production of backplanes are very expensive.
A shadow mask vapor deposition process is well known and has been used for years in microelectronics manufacturing. The shadow mask deposition process is a significantly less costly and less complex manufacturing process, compared to the photolithography process.
A problem of using the shadow mask vapor deposition process to form an active matrix backplane is that during one or more of the vapor deposition steps or events of said process a shadow mask placed in intimate contact with the source metal and/or the drain metal of one or more transistors of said backplane can accumulate a charge of static electricity, which accumulated charge can discharge and damage semiconductor material of said one or more transistors when the shadow mask is moved away from intimate contact with the source metal and/or the drain metal.